// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_OBJECTS_JS_COLLECTION_ITERATOR_H_
#define V8_OBJECTS_JS_COLLECTION_ITERATOR_H_

#include "src/globals.h"
#include "src/objects.h"
#include "src/objects/js-objects.h"
#include "src/objects/smi.h"

// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"

namespace v8 {
namespace internal {

    class JSCollectionIterator : public JSObject {
    public:
        // [table]: the backing hash table mapping keys to values.
        DECL_ACCESSORS(table, Object)

        // [index]: The index into the data table.
        DECL_ACCESSORS(index, Object)

        void JSCollectionIteratorPrint(std::ostream& os, const char* name);

        DEFINE_FIELD_OFFSET_CONSTANTS(JSObject::kHeaderSize,
            TORQUE_GENERATED_JSCOLLECTION_ITERATOR_FIELDS)

        OBJECT_CONSTRUCTORS(JSCollectionIterator, JSObject);
    };

    // OrderedHashTableIterator is an iterator that iterates over the keys and
    // values of an OrderedHashTable.
    //
    // The iterator has a reference to the underlying OrderedHashTable data,
    // [table], as well as the current [index] the iterator is at.
    //
    // When the OrderedHashTable is rehashed it adds a reference from the old table
    // to the new table as well as storing enough data about the changes so that the
    // iterator [index] can be adjusted accordingly.
    //
    // When the [Next] result from the iterator is requested, the iterator checks if
    // there is a newer table that it needs to transition to.
    template <class Derived, class TableType>
    class OrderedHashTableIterator : public JSCollectionIterator {
    public:
        // Whether the iterator has more elements. This needs to be called before
        // calling |CurrentKey| and/or |CurrentValue|.
        bool HasMore();

        // Move the index forward one.
        void MoveNext() { set_index(Smi::FromInt(Smi::ToInt(index()) + 1)); }

        // Returns the current key of the iterator. This should only be called when
        // |HasMore| returns true.
        inline Object CurrentKey();

    private:
        // Transitions the iterator to the non obsolete backing store. This is a NOP
        // if the [table] is not obsolete.
        void Transition();

        OBJECT_CONSTRUCTORS(OrderedHashTableIterator, JSCollectionIterator);
    };

} // namespace internal
} // namespace v8

#include "src/objects/object-macros-undef.h"

#endif // V8_OBJECTS_JS_COLLECTION_ITERATOR_H_
